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EK Bio 3
microbio
| Question | Answer |
|---|---|
| virus consists of … | protein coat with genes in the form of DNA or RNA inside (either not both), and some surrounded with lipid rich envelope |
| virion | mature virus outside the host cell |
| why are viruses not classified as living organisms? | always require host cell reproductive machinery, don’t metabolize organic nutrients (use ATP from host), in active form are not separated from external environment by barrier, can be crystallized w/o losing their ability to infect |
| viral infection begins with... | virus adsorbing to specific chemical receptor site on the host |
| lytic cell cycle | virus infects a cell, injects its nucleic acid and replicates its virus- assembles its viruses until cell burst (lyses) |
| lysogenic viral cell cycle | after virus infects a cell and injects its nucleic acid into the cell, it is integrated into the host cell chromosome to reproduce infected cells and can lay dormant until host cell is under some type of stress before it becomes virulent |
| reverse transcriptase | enzyme that can reverse transcribed from RNA and then incorporated into the host cell genome |
| provirus | when viral DNA remains incorporated in the host DNA and remains or dormant/latent |
| ways to classify viruses | type of nucleic acid they possess |
| plus strand RNA viruses | unenveloped ones are responsible for the common cold, indicates that the proteins can be directly translated from the RNA |
| enveloped plus strand RNA viruses | include retroviruses that include the HIV that carries the enzyme reverse transcriptase |
| minus strand RNA viruses | include measles, rabies, and the flu; complement to mRNA and must be transcribed to plus-RNA before being translated |
| how does the human body fight off viral infections? | with antibodies that bind to viral protein (spike proteins on envelope) and with cytotoxic T cells |
| viriods | related form of infectious agent, small rings of naked RNA w/o capsids and only infect plants |
| prions | naked proteins that cause infections in animals, and capable of reproducing themselves w/o DNA or RNA |
| vaccine | either an injection of antibodies or an injection of a nonpathogenic virus with the same capsid or envelope so host immune system can create its own antibodies |
| carrier population | viruses can continue to thrive in another animal thus maintaining the ability to reinfect the human population |
| prokaryotes | organsims that have no membrane bound nucleus |
| archea | 1 of 2 domains of prokaryotes that have much in common with eukaryotes, typically found in extreme environments like salty lakes and boiling hot springs with cell walls not made of peptidoglycan |
| bacteria | 1 of 2 domains of prokaryotes |
| phototrophs | organisms that acquire energy from light |
| chemotrophs | organisms that acquire energy from oxidation of organic or inorganic matter |
| autotrophs | organisms that are capable as using CO2 as their sole source of carbon - energy expensive process |
| heterotrophs | use preformed organized molecules as their source of carbon |
| prokaryotic DNA | usually single, circular dsDNA twisted into supercoils and associated with histones, found in nucleoid NOT enclosed in membrane |
| prokaryotic ribosome | smaller than eukaryotic ribosomes, made from 50S and 30S to form 70S |
| inclusion body | granules of organic or inorganic matter; sometimes bound to membrane |
| flagellum | composed of globular protein flagellin that rotate counterclockwise to propel bacteira and rotate clockwise to tumble |
| mesosome | invagination of plasma membrane, unknown function, and may or maynot be present in a prokaryote |
| fimbraie | can attach bacteria to solid surface |
| phospholipid is made of.. | phosphate group, two fatty acid chains, and a glycerol backbone |
| liposome | vesicle surrounded and filled by aqueous solution, and contains a lipid bilayer like that of a plasma membrane |
| integral membrane protein | aka intrinsic proteins - amphipathic proteins that transverse the membrane from inside of the cell to the outside |
| peripheral membrane protein | aka extrinsic - situated entirely on the surfaces of the membrane and are ionically bonded to integral proteins or polar group of a lipid |
| fluid mosaic model | model describing the plasma membrane - forces holding membrane together are intermolecular so membrane is fluid - so its parts can move laterally but not separate |
| what moderates membrane fluidity in eukaryotic membranes? | cholestroal |
| what moderates membrane fluidity in prokaryotic membraines? | hopanoids - reduce fluidity of the membrane |
| what to consider with permeability of membrane? | size and polarity |
| most diffusion of polar or charged molecules across a natural membrane taes place through... | incidental holes/leakage channels created by irregular shapes of integral proteins but is not meant to aid in diffusion |
| passive diffusion | diffusion where molecules move thru leakage channels across the membrane due to random motion |
| transport/carrier proteins | proteins designed to facilitate the diffusion of specific molecules across the membrane |
| facilitated diffusion | mechanism used by transport proteins to help specific molecules across membrane down electro-chemical gradient; often relied on for glucose supply in human cells, and makes membrane selectively permeable |
| active transport | reqd for movement against an electrochemical gradient, uses direct or indirect ATP |
| secondary active transport | uses indirect ATP - uses ATP to create electrochemical gradient then using the energy of the electrochemical gradient to acquire or expel a molecule |
| big and polar molecules will be transported across a membrane with... | facilitated diffusion |
| bacteria is protected from environment by | protoplast then bacterial envelope then cell wall |
| functions of bacterial cell wall | prevent protoplast from bursting |
| cell is hypertonic to their soln meaning .. | aqueous soln of their cytosol contains more particles than the aqueous soln surrounding tissue |
| cell is isotonic to their soln meaning .. | aqueous soln of their cytosol contains the same amt of particles than the aqueous soln surrounding tissue |
| cell is hyptonic to their soln meaning .. | aqueous soln of their cytosol contains less particles than the aqueous soln surrounding tissue |
| bacterial cell wall is made of.. | peptidoglycan |
| peptidoglycan | series of dissacharide polymer chains with amino acids that are connnected by their amino acids or cross linked; more ellastic than cellulose and porous so it allows large moelcules to pass thru |
| gram staining | staining technique use dto prepare bacteria for viewing under the light microscope |
| gram positive bacteria | have thick peptidoglycan cell wall which prevents the gram stain from leaking out so stain purple |
| gram negative bacteria | have thin peptidoglycan cell wall so they show as pink; have another phospholipid bilayer surrounding the cell wall that is more pemeable but contains lipopolysaccharides that form protective barrier from antibodies/antibiotics |
| bacterial capsule | can protect bacterium from phagocytosis, dessication, some viruses, and some componanets of host immune systems |
| slime layers | can wrap a bacteria to help protect it, but it can be washed away |
| three forms for genetic recombination for bacteria | conjugation, transformation, and transduction |
| conjugation | requires plasmid w/ gene that codes for the sex pilus |
| transformation | process by which bacteria may incorporate DNA form their external environment into their genome |
| transduction | uses the capsid of bacteriophage tin inject bacterial DNA into cell instead of virulent viral DNA (vector) |
| steps in bacterial conjugation | conjugative plasmid creates the sex pilus to connect two bacteria and allow passage of DNA - strand is replicated as it is separated, fed into pilus into other cell |
| F plasmid | fertility factor or F factor, first plasmid described, and can be in the form of an episome and can replicate some of the host chromosome |
| R plasmid | donates resistance of certain antibiotics |
| endospores | formed by some gram positive bacteria that can lie dormant for hundreds of years; resistent to heat, UV radiation, chemical disinfectants, and desiccation; triggered by lack of nutrient |
| fungi | eukaryotic heterotophs that obtain their food by absorption rather than ingestion, many saprophytic, possess cell walls made of chitin; lack centrioles; mitosis takes place entirely w/in nucleus; |
| chiting | polysachharide that makes up fungal cell walls, they are more resistant to microbial attacks |
| what stage dominates in fungi? (diploid or haploid) | haploid |
| fungi spores | haploid which give rise to new mycelia in asexual repoduction; borne by air currrents, water, or animals to locations suitable for new mycelial growth |
| asexual reproduction of fungi often occurs by... | budding - smaller cell pinches off from single parent cell |
| mechanisms for sexual reproduction for fungi | hyphae from two mycelia (+ & -) grow toward each other to form conjugation bridge to form complete septum - becomes gamete producing cell - separates from parent - activated by environment to undergo meiosis and produce haploid cells |
| growth state of fungi... | consist of tangled mass mycelium of multiply branched thread like hyphae |
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miniangel918
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